Comparative study of effects of isoproterenol and vasoactive intestinal polypeptide on voltage-dependent Ca2+ and Ca(2+)-activated K+ currents in porcine tracheal smooth muscle cells.
Effects of isoproterenol (Iso) and vasoactive intestinal polypeptide (VIP) on voltage-dependent Ca2+ channel (ICa) and Ca(2+)-activated K+ channel current (IK-Ca) in porcine tracheal smooth muscle cells were examined. When K+ currents were inhibited using a Cs-rich pipette solution, application of 0.1-1 microM Iso or 1-10 nM VIP increased ICa by 20-30%. On the other hand, IK-Ca elicited upon depolarization and spontaneous transient outward K+ currents (STOCs) recorded at a holding potential of -50 mV were enhanced by 80-100% in the presence of 0.1 microM Iso or 1 nM VIP.
Muraki
K
K
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Nagoya City University, Japan. kmuraki@phar.nagoya-cu.ac.jp
Imaizumi
Y
Y
Bolton
T B
TB
Watanabe
M
M
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D004594:Electrophysiology; D007545:Isoproterenol / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D011188:Potassium / Q000502:physiology; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D013552:Swine; D014132:Trachea / Q000187:drug effects* / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D015220:Calcium Channels; D015221:Potassium Channels; D014660:Vasoactive Intestinal Peptide; D007545:Isoproterenol; D011188:Potassium; D002118:Calcium